"William Cavendish, Duke of Newcastle (1592-1676) commanded the Royalists in northern England, and during 1643 made heavy work of defeating a small parliamentarian army. In 1644 he faced the invading Scots, and his tardiness in joining Prince Rupert before Marston Moor may have cost the Royalists victory. After the battle he fled to the Continent, where he wrote a book on horsemanship which remains his chief claim to fame."